In general, the supply of fluids and in particular oxygen, in gaseous form is required in a diverse number of medical situations. Depending on the specific medical condition observed, an enriched supply of oxygen over that of the ambient atmosphere, is often required. Such oxygen is normally supplied through a nasal cannula, which consists of two hollow prongs, each of which is inserted into a nasal nostril. The cannula is connected to a source of pure oxygen through a humidifying device, which allows the dry oxygen to be supplied with water or water vapor.
Other methods of providing oxygen to a patient utilize a variety of masks, such as a Venturi® mask, which cover both the nose and mouth of the wearer. In both the nasal cannula and/or mask designs, however, the gas is forced directly into the nose and/or mouth, with numerous drawbacks. First, depending upon the flow rate of the gas, the pressure of the impinging gas upon the relatively sensitive nasal membranes can be irritating and painful, as well as detrimental to the patient's condition. Typically, gas flow rates off Venturi® masks are between 105 liters per minute i.e., “lpm,” at the high end and 34 lpm at the low end, which can dry out a normal individual even using a heated humidifier in less than 2 hours. This often has the disadvantageous effect of rapidly drying the moist tissues caused by the nasal cannula and mask designs, which can lead to increased bronchial spasms and airway plugging. The higher the gas flow, the quicker the patient is subjected to tissue drying, desiccation, endothelial bleeding and cracking with associated increased airway plugging, infection and pneumonitis.
Secondly, as Venturi® breathing systems generate high flow rates, even at high concentrations of oxygen where the air mix resulting from air entrainment is low (35 to 50 lpm of flow) and impacts directly onto the patient/user's breathing orifices. Prior art devices direct such flow directly opposing the breathing orifices, resulting in rapid airway lining tissue drying, membrane cracking, bleeding and pain. Major adverse effects can be observed if a Venturi® system's airflow is directed as seen in prior art designs, confined to and into the nasal passages. These effects include severe repetitive nasal bleeding resulting from desiccated and cracked tissues, inspisated secretions of nasal epithelium and submucosa, as well as severe headaches, esophageal air swallowing, vomiting and aspiration, all with deleterious results, including yet not limited to aspiration pneumonitis.
The normal response of a conscious and mobile patient user is to remove the breathing device to alleviate the pain and discomfort resulting from such Venturi® devices, as seen clinically throughout intensive care units and wards. However, in neurologically and/or disabled and/or unconsciously breathing patient/user, the results of leaving such high flow devices as Venturi® masks are often aspiration of induced vomitus, pneumonia and severe hypoxia.
Additionally, in such prior art designs of the Venturi® mask or apparatus, both source gases and entrained air are directly perpendicular; meaning the total airflow produced is opposing the patient/users breathing orifices. As the increased velocity achieved by the Venturi® jet orifice acts on the incoming source gas, it creates an area of reduced pressure immediately post the exiting source gas jetted out—this causes air entrainment mixing with the source gas oxygen, opposite the patient/user's orifices. As such, any and all back pressure, such as resulting from forced expirations, coughing, pursed lip breathing is directed back onto and affects the “Venturi® Jet valves'” function. This, combined with the breathing rhythm changes as typically evidenced in Chronic Obstruction Pulmonary Disease (“COPD”) patients, further worsens the conditions the Venturi® mask was specifically designed to treat. This backpressure directed back to and onto the Venturi® jet valve can affect the effective flow rate of the oxygen and change the amount of oxygen available to the patient. Accordingly, the flow rate administered by the medical personnel is distorted. This can lead to erroneous flow data and potentially life-threatening situations.
Further, the use of a conventional mask is often a burden upon the patient and may be uncomfortable to wear. Use of a nasal cannula requires a source of pure oxygen, as well as apparatus for providing a source of water or water vapor. A device for combining such vapor with the oxygen is also required with these prior designs. What is needed is a Venturi® mask system configured to limit back pressure, provide the proper mixture of oxygen and other gases for breathing and to reduce the drying of nasal passages and orifices due to direct flow.
Therefore, what is needed in the field is an inhalation device specifically designed to overcome the disadvantages and drawbacks of the prior art. That is an improved inhalation device and related methods of use, adapted for disposal adjacent a nose and mouth of a subject, to supply a mixture of fluids, such as oxygen and ambient air, for inhalation by the subject.